Our invention relates to a dual-visor assembly for use with a helmet such as that worn by an aircraft crewmember or the like.
Dual-visor assemblies for aircraft crewmembers' helmets or the like are well known in the art. In one such assembly, shown in Aileo U.S. Pat. No. 3,601,813, an inner visor and an outer visor are controlled by respective actuator knobs that extend outwardly through slots formed in the visor housing. Each knob may be moved up or down along the slot to raise or lower the visor and may be rotated to clamp the adjacent slot wall and thus immobilize the visor. One obvious limitation of this assembly is that the inner visor cannot be lowered without also lowering the outer visor.
In another dual-visor assembly known in the art, the outer visor is controlled by a lever that extends laterally beyond the left edge of the visor, while the inner visor is similarly controlled by a lever that extends beyond the right edge of that visor. Each actuator lever is resiliently biased into engagement with a rack or series of detents to provide a nearly continuous range of locked positions. Although this latter assembly permits lowering of the inner visor independently of the outer visor, the fixed arrangement of the actuator levers limits the versatility of the visor assembly. Thus, it has been found that the optimum configuration of the visor actuators depends on a number of factors, including the type of aircraft that is being flown, whether the wearer's seat is on the left or on the right, whether the wearer is left-handed or right-handed, and the particular mission or activities of the wearer. Neither of the prior-art assemblies described above is fully adaptable to all of these changes in operating environment.